Why Rhododendron nakaharae instead of R. nakaharai?
Donald H. Voss
A rose by any other name may smell as sweet, but botanists and serious horticulturists believe that the proper naming of plants is not a trivial matter. Within a given genus, each plant should be known by only one specific epithet (and/or cultivar name, as appropriate) and such name should apply only to that plant. For many reasons - among them indifference - this objective may not be attained, but it is surely worth pursuing. Registration of cultivar names, described in the Plant Registry section in each issue of this journal, is an important step in the right direction. 
For plants originating in the wild (species, subspecies, etc.), nomenclature is governed by the International Code of Botanical Nomenclature (Botanical Code), successive editions of which have been adopted by International Botanical Congresses.  The Botanical Code also governs the use of botanical names in Latin form that were given to cultivated plants before 1 January 1959. After that date, new cultivar names generally may not be in Latin form. Consequently, agricultural, horticultural, and silvicultural cultivars (cultivated varieties) are now given "fancy names" (for example, 'Robin Hill Congo'). To promote uniformity, accuracy, and fixity in the application of cultivar names, the International Code of Nomenclature for Cultivated Plants (Cultivated Code) has been provided.  It is to this latter set of rules that we are indebted for the three-word limit on cultivar names (this is the reason, for example, that R.D. Gartrell on one occasion had to change "Robin Hill" into one word to make possible registration of the name 'Nancy of Robinhill').
The Species Named For G. Nakahara
The species R. nakaharae was first published as R. Nakaharai by the Japanese botanist B. Hayata in 1908. Working with specimens collected G. Nakahara on Mount Morrison, Taiwan (Formosa), Hayata determined that he had previously misidentified one of the Formosan plants as R. serpyllifolium Miq. Hayata stated: ... In sterile specimens, the two come so closely that it is difficult to distinguish one from the other. On comparing flowers, I have found that both plants entirely differ from each other. The new species differs from the other in having much larger flowers, long hairy sepals, and in the number of stamens.
In appreciation of G. Nakahara's efforts in collecting and making specimens available for study, Hayata named the new species R. Nakaharai and published the name, together with the appropriate Latin diagnosis, in the article cited above. Why, then, does the Royal Horticultural Society's The Rhododendron Yearbook 1980 , compiled by the International Rhododendron Registrar, use the form R. nakaharae ?  Why does Dr. John Creech, internationally recognized for his plant explorations in Japan and expertise on the Japanese species of Rhododendron , use the -e ending in adherence to the practice followed in Ohwi's Flora of Japan for Japanese names such as komiyamae , mayebarae , and tamurae ? 
Which Form Is Correct?
The answer lies in provisions of the Botanical Code:
* Recommendation 23A.1 - Names of men and women and also of countries and localities used as specific epithets may be substantives in the genitive ( clusii , saharae) or adjectives ( clusianus, dahuricus )...
* Recommendation 73C.1 - Modern personal names may be latinized and used to form specific and infraspecific epithets in the following manner...:
(a) If the personal name ends in a vowel or -er , substantive epithets are formed by adding the genitive inflection appropriate to the gender and number of the person(s) honored..., except when the name ends in -a when adding -e (singular) or -rum (plural) is appropriate (e.g. triana-e for Triana (m)).
* Article 73.10 - The wrong use of the terminations, for example -i , -ii , -ae , -iae , -anus , and -ianus , mentioned in Recommendation 73C.1 is treated as an orthographic error to be corrected.
* Article 73.1 - The original spelling of a name or epithet is to be retained, except for the correction of typographic or orthographic errors [emphasis added]. As to styling specific epithets with lower-case initial letters, Recommendation 73F.1 provides that "All specific and infraspecific epithets should be written with small initial letters, although authors desiring to use capital initial letters may do so when the epithets are directly derived from the names of persons..."
Ergo, Rhododendron nakaharae!
1. See, for example, American Rhododendron Society Journal, Vol. 43:1 (Winter 1989), The procedures are also discussed in "Introduction, Registration, and Printing Format Of Named Azalea Cultivars," The Azalean , Vol. 7:4 (December 1985); "The Registration Of Named Azalea Cultivars," Letter to the Editor from the International Rhododendron Registrar, The Azalean , Vol. 8:2 (June 1986), p. 46.
2. Stafleu, F.A., etal. International Code of Botanical Nomenclature Adopted by the Twelfth International Botanical Congress, Leningrad, July 1975. Utrecht: Bohn, Scheltema, & Holkema, 1978.
3. Brickell, CD., etal. International Code of Nomenclature for Cultivated Plants - 1980 Formulated and adopted by the International Commission for the Nomenclature of Cultivated Plants of the I.U.B.S. Utrecht: Bohn, Scheltema, & Holkema, 1980.
4. Hayata, B. "Flora Montana Formosae... "Journal of the College of Science, Imperial University, Tokyo, Japan . Vol. XXV, Article 19. Tokyo: 1908. P. 153.
5. Leslie, Alan (compiler). The Rhododendron Handbook 1980: Rhododendron Species in Cultivation . The Royal Horticultural Society. London, 1980. P. 179.
6. Personal communication from Dr. Creech, 30 June 1988.
Author's note: The author is indebted to Dr. T.R. Dudley, US National Arboretum, for reading and commenting on a draft of this note. Any lapses or errors in the final text are solely the responsibility of the author.
Donald Voss, Potomac Valley Chapter member, is on the board of directors, Azalea Society of America. He is a frequent contributor to the journals of both the ARS and the ASA.